W3C CSS Working Group Publishes Three Cascading Style Sheets Working Drafts.

The W3C CSS Working Group has released three working drafts for the Cascading Style Sheets language "which is widely implemented and is playing an increasingly important role in styling many kinds of XML documents, including XHTML, SVG (Scalable Vector Graphics), XML, and SMIL (Synchronized Multimedia Integration Language). As described in CSS3 Module: Presentation Levels, presentation levels are integer values attached to elements in a document. They can be used to support slide presentations with transition effects (e.g., progressively revealing a list item by sliding it in from the side) and outline views of documents. The CSS3 Module: Syntax specification "describes the basic structure of CSS style sheets, some of the details of the syntax, and the rules for parsing CSS style sheets. It also describes how stylesheets can be linked to documents and how those links can be media-dependent." The CSS Print Profile is designed for printing from mobile devices where it is not feasible or desirable to install a printer-specific driver, and for situations were some variability between the device's view of the document and the formatting of the output is acceptable to provide a strong basis for rich printing results without a detailed understanding of each individual printer's characteristics. This profile will work in conjunction with XHTML-Print and defines an extension set that provides stronger layout control for the printing of mixed text and images, tables and image collections." The W3C CSS Working Group requests feedback on the working draft specifications.

"Content reuse has been one of the main motivations for the development of style sheets. By associating documents with different style sheets, the same content can be presented in different ways. The introduction of presentation levels in CSS adds functionality which is very useful in two particular settings. First, slide presentations with transition effects can be described. For example, list items can be progressively revealed by sliding in from the side. Second, outline views of documents, where only the headings to a certain level are visible, can be generated."

"The model behind presentation levels is simple. Each element in the document is assigned an integer value which is referred to as the 'element's presentation level' (EPL). The EPL can be set explicitly in a style sheet or calculated automatically based on the element's position in the document structure: it is specified by the computed value of the 'presentation-level' property. The User Agent maintains another integer value which is called the User Agent Presentation Value (UAPL). The UAPL starts at a UA-defined value, typically 0."

"All elements are in one of three presentation pseudo-classes: 'below-level', 'at-level', and 'above-level'. These pseudo-classes refer to whether the element's EPL was below, at, or above the UAPL the last time the UAPL changed. When an element's state is evaluated, the EPL is compared to the UAPL and pseudo-classes are assigned as follows: If the EPL is equal to 0, the element is always in the below-level state. If the EPL is lower than the UAPL value, it is set to the 'below-level' state, if the EPL is exactly that value it is set to 'at-level', and if the EPL is greater than that value it is set to 'above-level'..."

"This specification defines a subset of the Cascading Style Sheets Level 2 specification with additions from the proposed features of CSS3 module: Paged MediaPaged Media Properties for CSS3, specifically for printing to low-cost devices. It is designed for printing from mobile devices, where it is not feasible or desirable to install a printer-specific driver, and for situations were some variability between the device's view of the document and the formatting of the output is acceptable to provide a strong basis for rich printing results without a detailed understanding of each individual printer's characteristics."

"This profile is designed to work in conjunction with XHTML-Print and defines a minimum level of conformance as well as It also defines an extension set that provides stronger layout control for the printing of mixed text and images, tables and image collections."

"The specification is a public Working Draft from the CSS working group, which is part of the Style activity and is released with the consensus of the group. It is based, in large part, on a work by the same name, CSS Print Profile from the Printer Working Group (PWG), a program of the IEEE Industry Standard and Technology Organization (IEEE-ISTO)..."

"This CSS3 module describes the basic structure of CSS style sheets, some of the details of the syntax, and the rules for parsing CSS style sheets. It also describes (in some cases, informatively) how stylesheets can be linked to documents and how those links can be media-dependent. Additional details of the syntax of some parts of CSS described in other modules will be described in those modules. The selectors module has a grammar for selectors. Modules that define properties give the grammar for the values of those properties, in a format described in this document.

"This document is a draft of one of the modules of CSS Level 3 (CSS3). Some parts of the document are derived from the CSS Level 1 and CSS Level 2 recommendations, and those parts are thus relatively stable. However, it is otherwise an early draft, and considerable revision is expected in later drafts, especially in formalization of error handling behavior, the conformance requirements for partial implementations (given the modularization of CSS3), and integration with other CSS3 modules..."

What are Style Sheets?

An introduction to style is presented in the W3C Web Style Sheets home page: "Style sheets describe how documents are presented on screens, in print, or perhaps how they are pronounced. W3C has actively promoted the use of style sheets on the Web since the Consortium was founded in 1994. The Style Activity has produced several W3C Recommendations (CSS1, CSS2, XPath, XSLT). CSS especially is widely implemented in browsers. By attaching style sheets to structured documents on the Web (e.g. HTML), authors and readers can influence the presentation of documents without sacrificing device-independence or adding new HTML tags... The W3C Style Activity is also developing XSL, which consists of a combination of XSLT and 'Formatting Objects' (XSL-FO)..."

W3C CSS Specifications List

The CSS Roadmap provides an overview of CSS3 Modules and other CSS specifications, including completed Recommendations, Candidate Recommendations, Working Drafts, Notes, etc. A table shows the development status for each, including projected completion dates for work in progress. Snapshot from 2003-08: